A photo-detecting apparatus is an apparatus comprising a plurality of photodiodes arranged one- or two-dimensionally, and an integrating circuit including an amplifier and a capacitor. In this kind of photo-detecting apparatus, the photodiodes output respective electric charges corresponding to their incident light intensities. The capacitor accumulates thus outputted electric charges, whereas the integrating circuit outputs voltages corresponding to thus accumulated electric charges. In accordance with the output voltages of the integrating circuit, the photo-detecting apparatus detects incident light at photosensitive regions corresponding to positions where the photodiodes are arranged.
Known as an example of this kind of photo-detecting apparatus is one disclosed in Japanese Patent Application Laid-Open No. 2001-242253 (Document 1). In the photo-detecting apparatus disclosed in Document 1, one integrating circuit is provided for a plurality of photodiodes, whereas switches are provided between an input terminal of the integrating circuit and the respective photodiodes. The photodiodes are disposed on a first substrate, whereas the integrating circuit is disposed on a second substrate. Respective end parts of the first and second substrates are electrically connected to each other by wire bonding.